This invention is directed to an exhaust gas turbine with movable vanes wherein pressure is sensed at the inlet and outlet of the vanes to control the vanes for adjusting their angle and nozzle openings to maximize efficiency.
Modern internal combustion engines can supply greater output power when their cylinders are charged with more air through the use of a charging compressor, along with a corresponding increased supply of fuel. A centrifugal compressor is often used for this purpose and an exhaust gas turbine drives the charging compressor current. Commercially available turbochargers are of a type where the housing directing the exhaust gas to the turbine is of the open volute type which has a fixed entrance area. Such fixed area housings do not provide optimum efficiency over the turbine operating range. This is because the operating conditions diverge from the optimum conditions for which that turbine was designed. At low engine speed, the turbine requires smaller inlet area, while the large exhaust gas flow at high engine rpm requires a large inlet area. Hence, the fixed housing inlet area designs of current commercial turbochargers have design compromises causing poor transient response time (turbo-lag), poor fuel economy, high exhaust manifold pressures at high and low engine rpm, and severe detonation in gasoline fueled engines under some operating conditions.